Efficient way of updating colors of model3d elements

Question

I'm using a Viewport3DX with a lot of different MeshGeometryModel3D elements. The User Interface integrates a slider that will update the opacity (alpha-value of PhongMaterials) of all model3d elements.

This is my current implementation of the code that updates the opacity:

geometryhandler.cs

       public void UpdateOpacity(double value)
       {

           if (_mainWindow.MyBuildingComponents == null) return;

           foreach (var component in _mainWindow.MyBuildingComponents)
           {

               // assign new material and later assign it back, to get the changes of the material recognized
               var newmaterial = (_meshIdTogeometryModel3D[component.Id].Material as PhongMaterial).Clone();

                // create new DiffusColor because setting the alpha property directly is not possible
               newmaterial.DiffuseColor = new Color4(newmaterial.DiffuseColor.Red, newmaterial.DiffuseColor.Green, newmaterial.DiffuseColor.Blue, (float)value);

               _meshIdTogeometryModel3D[component.Id].Material = newmaterial;
             
           }

       }

MainWindow.xaml.cs

        private void UpdateOpacity(object sender, RoutedPropertyChangedEventArgs<double> e)
        {
            Geometryhandler?.UpdateOpacity(SliderModelOpacity.Value);
        }

The UpdateOpacity function is called each time the value of the slider changes, iterates through a dictionary of MeshGeometryModel3D elements and updates their materials.

I tried many different version, but in the end this was the only implementation that did the job. However the update is very slow and 'laggy', even in release mode.

I recognized two things:

• I had to clone the existing material, update it and assign it back to get the material to change in the viewport

• I couldn't directly set the alpha-property of the Diffusecolor, but instead instantiate a new color object

Does somebody have an idea where the bottleneck might be here. Is it the cloning of the material, instantiating the new color or both? Or something completely different? Are there any better ways of doing the updates? Curious to hear your suggestion. Thanks a lot already!

Answer 1

I'm going to reference my comment here so we can close out this question.

Are you using the "ValueChanged" event to trigger the UpdateOpacity? You might want to look into only updating the Opacity when the user is done dragging the slider: social.msdn.microsoft.com/Forums/vstudio/en-US/…. The only other suggestion I have is to try and combine/group together elements that have the same base color, so there are fewer material changes required with the opacity update.

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msdn.microsoft.com/en-us/library/bb613553.aspx